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@niiet tetrs atent @frn `WILLIAM HURLBUT, OF EL-GIN, ILLINOIS.

Letters Patent No. 63,254, dated llfarct 26, 1867.

IMPROVEMENT IN CONVERTING MOTIQN.

TO ALL WHOM IT MAY CONOERN:

Be it known that I, WILLIAM I-I. HURLBUT, of Elgin, Kane county,l Stateof Illinois, have invented a new and useful Improvement in ConvertingMotion and I do hereby declare that the following is a full, clear, andexact description thereof, which will enable others skilled in the artto make and use the same, reference being had to the accompanyingdrawing, forming part of this specification, in which- Fig-ure Irepresents a plan or top view of this invention.

Figure 2 is a side sectional elevation of the same.

Similar letters of reference indicate like parts.

This inventionl consists in the employment or use of a spiral flangedcam, in combinatidn with the cross-head of a steam engine, or otherequivalent part of another motor, and with a shaft to whicha revolvingmotion is to be imparted in such a manner that by the action of thecross-head or other equivalent part on the spiral flanged cam thereciprocating motion of the 'piston of a steam engine or thereciprocating motion of an equivalent part of another motion isconverted into a continuous rotary motion of the shaft, said spiralflanged cam acting as a substitute for the crank.

A represents the cross-head of a steam engine, to which a reciprocatingmotion is imparted by the action oi' the steam lon the steam piston.From the lower surface of this cross-head project two pins, a, whichstraddle one of the wings of the spiral flanged cam Bf This camismounted on the main shaft C, and as the cross-head receivesits motiona continuous revolving motion is imparted by its action to the shaft C.The spiral ilanged cam is made by turning a block of wood or othermaterial the length of stroke required and of the same diameter. On thisblock I strike parallel lines through the centre on both. heads, and byconnecting the ends of these lines on the circumference ot' the block Iobtain' two lines, which, when the diameter of said block is ten inches,will be ten inches apart and parallel to each-other. I then open thedividers somewhat less than half the diameter of the block and describearcs from the opposite ends of leach of the side lines, and then I openthe dividers to the full half width of the diameter of thc block anddescribe two other arcs, the distance between the two arcs describedfrom the end -ofeach side line forming the thickness of the flanges orwings of the cam. After repeating this operation on the opposite end of,the block, I remove the wood or other material 'to the centreof theblock, leaving vthose parts between the' arcs intaet, and by these meansa spiral l'ianged cam is formed which produces the desired effect. Thisilanged cam takes the place ofthe crank, and it has the great advantagethat the power is applied always at the same distance from the centre ofthe shaft, and under the most favorable cireumstanceaso that nodead-centre exists, and a continuous revolving motion will be impartedto the shaft without requiring a ily-wheel. It is obvious that my spiralflanged cam can be applied in all cases where a reciprocatingrectilinear motion is to be converted into continuous rotary motion. Itwill be seen that the spiral flanged cam B B isso constructed at eachend as to avoid dead-points at the change of stroke for the back orreverse motion of the piston-rod. This is accomplished by soconstructing the cam at its ends that when the outside pin passes thepoint o, (see fig. 2,) at the extreme outer end of the cam, the insidepin at this moment being the propelling power, passes on to 0, and doesnot pass the point o, or dead-point, until the outside pin passes thepoint o, when the reverse motion of the piston-rod takes place, and theoutside pin then becomes the propelling power until it reachesjtheopposite end of the cam.

I do not claim converting reciprocating into rotary motion by means ofthe employment of a shaft and cross-head, the former having a spiralflanged cam arranged upon the shaft, irrespective ofthepeculiarly-shaped ends of the cam to obviate dead-points, as this changeof motion may be seen in the patent of Nathan Atherton, dated October31, 1854; but what I do claim as my invention, and desire to secure byLetters Patent, is-

The spiral flanged cam B, having its ends constructed as described, incombination with the cross-head A, and pins a a, of a steam engine, orwith an equivalent part of any other motor, and with the shaft C, thewhole being constructed, arranged, and operated substantially inthemanner and for the purpose set forth.

i WILLIAM H. HURLBUT.

Witnesses;

A. HOAGLAND, J. W. HOAGLAND.

